Differences between English and Arabic are examined to assist the English as a second language (ESL) teacher. It is suggested that in order to know how to help students, ESL teachers must understand what the problem or difference is and why it is occurring. The sound systems of English and Arabic, including the suprasegmentals of intonation, stress, and rhythm, are contrasted, along with selected grammatical features. Attention is directed to contrastive features that not only cause semantic confusion, but also those that may trigger an emotional response not intended or realized by the Arabic speaker of English. All the vowels in English are, with one exception, in Arabic. Among the issues in teaching vowels to Arabic students is to lengthen the four long vowels in English; this is important in working on stress and unstress. In relation to consonants, the Arabic speakers tend to aspirate stop sounds in English in all positions, a practice which may make them appear overly strong and aggressive. Additionally, it is recommended that oral and written work is needed to teach the English final consonant clusters that are not permitted in Arabic. Another important thing to know is that monosyllabic words in Arabic are always stressed. This and other differences in the oral language patterns cause interference in controlling rhythm, intonation, and stress. Contrastive data and examples of errors are presented, based on work with intermediate and advanced students. (SW)